Roller crusher and method for operating thereof

Abstract

A roller crusher having two generally parallel rollers arranged to rotate in opposite directions, towards each other, and separated by a gap, where each roller having two ends. The roller crusher includes a flange attached to at least one of the ends of one of the rollers. The roller crusher further includes at least one mechanical scraper and a remote material removal device configured to output a material removing beam towards a target area. The at least one mechanical scraper and the remote material removal device are arranged consecutive to each other at an end of the roller with a flange for at least partially removing material accumulated on the flange and/or on the outer surface at the end of the roller. A method for operating a roller crusher is also provided.

The invention claimed is: 
     
       1. A roller crusher having two parallel rollers arranged to rotate in opposite directions, towards each other, and separated by a gap, each roller having two ends, the roller crusher comprising:
 a flange attached to at least one of the ends of one of the rollers, 
 the flange extending in a radial direction of the roller, 
 the flange having a height (H) above an outer surface of the roller, wherein the roller crusher further comprises at least one mechanical scraper and a remote material removal device configured to output a material removing beam towards a target area, wherein the at least one mechanical scraper and the remote material removal device are arranged consecutive to each other at an end of the roller with the flange for at least partially removing material accumulated on the flange and/or on the outer surface at the end of the roller. 
 
     
     
       2. The roller crusher as claimed in  claim 1 , wherein the at least one mechanical scraper and the remote material removal device are arranged at a lower part of the roller crusher. 
     
     
       3. The roller crusher as claimed in  claim 1 , wherein the at least one mechanical scraper is arranged such that a scraping surface of the at least one scraper at least partly face downwards for allowing removed material to leave from the roller and scraping surface by gravitational force. 
     
     
       4. The roller crusher as claimed in  claim 1 , wherein the remote material removal device is a fluid jet knife. 
     
     
       5. The roller crusher as claimed in  claim 4 , wherein the fluid jet knife device is an air knife. 
     
     
       6. The roller crusher as claimed in  claim 1 , wherein the target area of the remote material removal device is located in front of the at least one mechanical scraper. 
     
     
       7. The roller crusher as claimed in  claim 1 , wherein the material removing beam is directed opposite to a tangential velocity of the roller at the target area. 
     
     
       8. The roller crusher as claimed in  claim 1 , wherein the roller crusher further comprises a wear-protective arrangement for the remote material removal device. 
     
     
       9. The roller crusher as claimed in  claim 8 , wherein the wear-protective arrangement has an opening through which the material removing beam of the remote material removal device exits. 
     
     
       10. The roller crusher as claimed in  claim 8 , wherein the wear-protective arrangement further comprises a wear guard for protecting a body of the remote material removal device. 
     
     
       11. The roller crusher as claimed in  claim 1 , wherein the scraping surface of the at least one mechanical scraper is arranged such that a distance between the outer surface of the roller and the scraping surface decreases towards the flange. 
     
     
       12. The roller crusher as claimed in  claim 1 , wherein the at least one scraper has a fastening position located at a distance from the outer surface of the roller, wherein the at least one scraper is arranged such that a position of a scraping surface of the at least one scraper is located at, or consecutive to, a radial axis which extends from a rotational axis of the roller and through the fastening position. 
     
     
       13. The roller crusher as claimed in  claim 9 , wherein the target area of the remote material removal device is located in front of the at least one mechanical scraper and wherein the roller crusher further comprises a holding fixture for the at least one mechanical scraper which holding fixture has the opening through which the material removing beam of the remote material removal device exits and which holding fixture forms part of the wear-protective arrangement. 
     
     
       14. The roller crusher as claimed in  claim 1 , wherein the remote material removal device is arranged on the roller crusher such that a direction of the material removing beam is adjustable. 
     
     
       15. The roller crusher as claimed in  claim 1 , wherein the roller crusher further comprises a controller configured to control operation of the remote material removal device to allow intermittently removing material accumulated on the flange and/or on the outer surface at the end of the roller by means of the remote material removal device. 
     
     
       16. The roller crusher as claimed in  claim 15 , wherein the roller crusher further comprises a roller crusher monitoring system configured to determine roller crusher monitoring system data pertaining to the build-up level of material accumulated on the flange and/or on the outer surface at the end of the roller, and wherein the controller is configured to control operation of the remote material removal device based on said roller crusher monitoring system data. 
     
     
       17. The roller crusher as claimed in  claim 16 , wherein the roller crusher monitoring system comprises one or more from:
 at least one monitoring camera arranged to monitor the at least one mechanical scraper and/or the remote material removal device, 
 at least one strain gage arranged on the at least one mechanical scraper and/or on a scraper fixture, and 
 at least one strain gage arranged on the flange. 
 
     
     
       18. A method for operating a roller crusher for grinding granular material, wherein the roller crusher has two parallel rollers arranged to rotate in opposite directions, towards each other, and separated by a gap, each roller having two ends, the roller crusher comprising:
 a flange attached to at least one of the ends of one of the rollers, 
 the flange extending in a radial direction of the roller, 
 the flange having a height (H) above an outer surface of the roller, wherein the method comprises at least the steps of: 
 a) providing at least one mechanical scraper and a remote material removal device consecutive to each other at an end of the roller with the flange, the remote material removal device configured to transmit a material removing beam toward a target area; 
 b) utilizing the at least one mechanical scraper to at least partially remove material accumulated on the flange and/or on the outer surface at the end of the roller; and 
 c) utilizing the remote material removal device to at least partially remove material accumulated on the flange and/or on the outer surface at the end of the roller, 
 wherein step b) is performed continuously and wherein step c) is performed at least intermittently. 
 
     
     
       19. The method as claimed in  claim 18 , wherein step b) results in a first thickness of accumulated material remaining on the flange and/or on the outer surface at the end of the roller, and step c) results in a second thickness of accumulated material remaining on the flange and/or on the outer surface at the end of the roller, and wherein the first thickness is larger than the second thickness. 
     
     
       20. The method as claimed in  claim 18 , wherein step c) is performed within predetermined time ranges. 
     
     
       21. The method as claimed in  claim 18 , wherein the at least one mechanical scraper comprises a trigger scraper positioned at a maximum tolerable distance from the roller surface and/or inner surface of the flange, which trigger scraper is configured to initiate step c) upon impact with accumulated material remaining on the flange and/or on the outer surface at the end of roller. 
     
     
       22. The method as claimed in  claim 18 , wherein step c) is performed at time positions determined by roller crusher monitoring system data pertaining to the build-up level of material accumulated on the flange and/or on the outer surface at the end of the roller. 
     
     
       23. The method as claimed in  claim 18 , wherein step c) is performed prior to shut-down of the roller crusher for allowing removing material accumulated on the flange and/or on the outer surface at the end of the roller for facilitating replacement of the at least one mechanical scraper.